Relay construction



l 'aten ted Apr. 24,

U N I TED STATE PAT EN T OF Fl CE 2,550,578 7 RELAY coNs'rRU'rioN RobertK. McBerty, Galion, Ohio, :assignor "to The North lllcctricManufacturing Company,

Galion, Ohio, a "corporation of Ohio Appucaiio'n aya), 1946,SerialNo.-d73,195

'2 Claims. (01. 200-87) over the relay construction disclosed in the'co-' pending application of Frank R. 'McBerty, Serial No. 652,335,filed March- 6, 1946 and assig ne'd'to the assignee of this application.7

The relay construction, to which the present inventionrelates,-comprises a plurality-ofmetallic reeds of stainless steel whichare stationarily mounted near one end and are arranged to be flexed byelectromagnetic means attracting an elongated armature carried near thefree end thereof. Generally a number of 'reeds is em ployed for eachrelay, the number depending upon the circuitconnectionsthat are to becontrolled. Of course, a single reed and armature can be employed.

Since the voltage applied to telephone circuits is relatively low, onlyaslight movement of the reed and armature is required for opening orclosing a circuit. Because'of this slight'movemerit-particular careis-taken to limit the movement of the reed-and armature 'awayffromthecooperating electromagnetic means and stationary contact. For thispurpose a back stop in the'form'ofa round glass rod has been us'ed. Thisrod has been positioned transversely'of the reeds and the constructionthereof 'Wlth respect .to the 'mounting of the armature thereon has beensuch that the armature, which is formed of -relatively soft magnetic'material such as a nickel iron alloy, has been allowed "to engage :theback stop. After repeated operations of therelay and a corresponding'number'of engagements of the armature or armatures with theback stop,ithas beenfoun'dthatthe-arma ture,-because of its being formed ofrelatively soft metal tends to wear away and "produce a finemetaldust-on the backstop. IILthGjPIZQS- ence of -moisture this dust hasadhesive characteristics such that-the armature tends to stick to theback stop, in certain circumstances and theattractive force applicabletothe-armature by the electromagnetic means is not sufli'cient to.pullthe same-away arid operate the contact Inthe-copendingapplication ofFrank R. Mc- Berty,above referred to, this difficulty was over come :bypositioning the reed in a longitudinal slotfalongoneiside of:thearmature with the reed extending slightly above" thesurface of the'arm'ature. The armature was then deformed to cause the sides of the slot togrip' the reed =therebetween and then the reed was spot welded to thearmature. The portion of the reed extend-'- ing from the surface of thearmature [was per mitted to engagethe'glass rod back stop. In thismanner the wearing away of the armature was prevented .sincesubstantially only point contact engagement was present'between therelatively ,hard round metallic reed and the round glassrod back stop.'The :present'i'nventijon ac? 'complish'es this same result in asomewhatmore expeditious and satisfactory manner. I

The object of myinven'tion, generally stated,

is to provide a telephonerelay type of contact construction which shallbe simple, efficient and long lived in operation and which ,may bereadily and economically manufactured.

Another object is to secure an armature to ametallic reed to form atelephone relay type of contactfinger so as "to provide substantiallpoint contact engagement betweenthe reed and a back stop while the majorportion of the reed coextensive with the armature is positioned belowits "surface. a H

Another object is to simultaneously deform a-portion of the armaturesubstantially around the metallic reed while relieving another portionof "the armature alongthereed'so that the latter will project slightlyfrom the former to permit contact engagement with aback stop solely bythe relatively hard metallic re'efd.

Other objects of-my invention will, in part, be obvious and in partappear hereinafter.

My invention is disclosed in the embodiment thereof shown in theaccompanying drawing and it comprises thefeatures of construction andarrangement "of "parts which will be exemplified in" the constructionhereinafter set .forth. and the scope of the application of which willbeindicatedin the appended'claiins. H a a For a morecomplete understandingof the nature and scope of my invention reierence'can be had to the"following detailed description taken in connection ,with 'theaccompanying drawing, in which; I

Figure 1 is a view, partly in end elevation and partly-in section,showing a tens -relay1in which my invention is incorporated; a

Figure '2 is a view, at an enlarged scale; side "elevation of one ofthe-metallic reeds with its armature mounted adjacent 1 the cooperatingstationary contact ofthe relayshown in'l 'igure 1. FigureB isaviewygpatrtl in sideelevation and partly insectiori, of-the upperportion of the reed carrying the arainture and-the stationary contactshown in Figurez;

Figure 4 is a perspective view of a portion of the armature, showing howit is relieved to expose a portion of the reed for contact engagementwith the back stop; and

Figure is a detail sectional view, taken along the lines 55 of Figure 4.

Referring now particularly to Figure 1 of the drawing, it will beobserved that the reference character l3 designates, generally, a relay,such as a tens relay, in which the present invention may beincorporated. It will be understood that this particular relay is shownmerely for illustrative purposes and that the invention can be used inother relays to solve the problem of sticking of the contact fingers tothe back stop which has been described in detail hereinbefore.

The relay comprises electromagnetic means including a coil ll disposedon a core I2 which extends upwardly from a back bar I3 and along thesides of which side plates I4 and I5 extend toward a pole piece [6 whichis carried by the upper end of the core I2. As set forth in thecopending application of Frank R. McBerty, above referred to, the backbar [3 supports a plurality of tens relays which together make up a linkthat forms a part of an all relay telephone exchange system.

Mounted on the pole piece 16 is a block 2i of insulation of a characterwhich can be molded readily about stationary contact members 22 thatextend upwardly therefrom to various heights to permit paralleling withsimilar contact members of other relays. Each contact member 22, whichis preferably formed of German silver, has a reentrant portion 22extending, as shown in Figure 3, into the block 2| of insulation tofacilitate molding and holding the same in place. At its lower end thecontact finger 22 is provided with an insert 23 of wear resisting metal,such as a gold alloy, which has a centrally located groove 24 to permitdouble contact engagement therewith by a transverse erosion resistingcontact member 25 which may also be a gold alloy. The contact member 25is carried at the upper end of an armature, shown generally at 26 on theside thereof adjacent the insert 23. When the armature 26 is attracted,as by energization of the coil I l it will be understood that it movestoward the stationary contact 22 and carries the contact member 25therewith into contact engagement with the insert 23. The armature 26 ispreferably formed of a nickel-iron alloy which provides the desiredmagnetic characteristics.

The armature 26 is mounted on the upper end of a flexible metallic reed2! which is preferably formed of stainless steel. The reed 2'! isflattened, as indicated at 28 in Figure 2, intermediate its ends tofacilitate its being molded and held in place in strip 29 of suitableinsulating material, it being understood that each strip 29 has moldedtherein a number of the reeds 21, the number depending upon the type andcharacter of the relay employed. Connection to the metallic reed 27 isprovided at the lower end thereof which projects below the strip 29. Asindicated in Figure 1, the strips 29 carrying the reeds 21 may be heldin place along the back bar l3 by suitable screws 33.

The metallic reed 27 is so arranged and positioned with respect to thestationary contact member 22 that its inherent resiliency tends to biasit away therefrom. Ror proper operation of the several movable contactfingers making up the relay If), it is essential that the armatures 26and reeds 21 supporting the same be uniformly spaced away from the polepiece N1 of the elecreceive the reed 21.

tromagnetic means. For this purpose a back stop 34 in the form of aglass rod is mounted transversely of the contact fingers and, as shownin Figures 1 and 3, is located along the upper ends thereof. Asindicated hereinbefore, when the armature 26 has been so constructedthat it, rather than the reed 2l, engaged the back stop 34, substantialwear of the armature took place resulting in the deposition of finemetallic powder on the back stop 34. This tended to cause sticking ofthe armature 26 to the back stop 34.

' Now, in accordance with my invention, as herein disclosed, I haveprovided a simple and effective way for mounting the armature 26 on themetallic reed 27 so that the latter rather than the former provides thesole contact engagement with the back stop 34.

This construction is shown more clearly in Figures 4 and 5 of thedrawings. As there shown, the armature 26 has a longitudinally extendinggroove 35 along one side thereof. The groove 35 is centrally located andis of sufiicient width to In order to hold the armature 26 in place onthe reed 2? and to provide good mechanical and electrical engagementtherebetween, the armature 26, with the reed 2'! in place in the groove35, is positioned in a suitable die of a press where Sllfi'lClBlltpressure can be applied to the opposite sides 36 of the armature 26 soas to deform it around the reed 21 with the edges of the slot 35, asindicated at 31, extending over the reed 27 to a substantial extent sothat the reed 2? is located below the surface 38 of the armature 26.

At the same time that the edges 3! of the groove 35 are being deformed,as just described,

the remaining surface 33 of the armature 26 isrelieved by application ofsufficient pressure thereto and at the same time the sides 4| arecorrespondingly deformed outwardly slightly beyond the sides 36. Thisexposes a portion 42 of the reed 21 so that the outer edge thereof isspaced from the surface 39 and, as shown in Figure 3, can havesubstantially point contact engagement with the round glass rod backstop 7 34. In this manner, in a single operation the "armature 23 ismechanically and electrically connected to the reed 21 and a portionthereof is relieved to provide point contact engagement with the backstop 34.

Solely for the purpose of illustration and in order to indicate designdimensions which may be used in practicing my invention I call attentionto the fact that the stainless steel reed 2'! may have a diameter of.016. For one particular type of relay it is 21% long. The armature maybe 5% long and the width thereof between the sides 36 may be .078". Thesurface 39 is relieved for about along the reed 2'! and the sides 4| ofthis portion are spaced .088 apart. The section 42 of the reed 27 alongthe relieved portion of the armature 26 extends above the surface 39about .OO. Using these particular dimensions for the type of relayreferred to in the construction and manufacture of the movable contactfinger it has been possible to eliminate entirely sticking to the backstop 34.

Since certain further changes can be made in the foregoing constructionsand method and different embodiments of the invention can be madewithout departing from the spirit and scope thereof, it is intended thatall matter shown in the accompanying drawing and described hereinbeforeshall be interpreted as illustrative and not in a limiting sense.

I claim as my invention:

1. Method of making a reed type, contact finger which comprisespositioning a metallic metal of a comparatively tough characteristiccompletely within a longitudinal slot in one side of an elongatedarmature of a softer type magnetic alloy, deforming portions of the sideof said slot around said reed for a substantial portion of the armaturelength to effect frictional attachment thereb'etween and incasement ofsaid reed for said substantial length, and relieving the brief remainingportion of the sides of said slot sufficiently to permit only thesection of said reed which is coextensive therewith to project above theedges of the slot and said relieved portion of the armature surface,whereby the exposed reed portion of said tougher material forms adurable contacting sur face for engaging contact positioning members onan associated relay structure.

2. In a telephone type relay having at least one set of circuitcontrolling members comprising a stationary contact, a movablecontact-bearing member, limit means for normally positioning thecontact-bearing member in a given position, and electromagnetic meansfor operating said movable member under tension from said given positionto a second position to effect engagement of said stationary and movablecontacts for circuit controlling purposes, said contact-bearing membercomprising a metallic reed stationarily mounted at its one end, anelongated armature having a longitudinally extending slot in one sidethereof which substantially inoases and frictionally engages said reedfor a substantial portion of the length of said armature and which isrelieved for a brief portion to permit an outer face of said reed toextend above said relieved armature surface for a correspondingly shortportion of their coextensive lengths, said armature being disposed toefiect engagement of said briefly exposed coextensive reed portion withsaid limit means upon the tensioned return of said contact-bearingmember to said first given position, whereby said tougher reed member isadapted to absorb the wear normally inflicted on said armature in saidtensioned return and said frictional incasement of said reed by saidarmature for said substantial length is effective to minimize flexingand relative movement of the reed and armature resulting therefrom.

ROBERT K. McBERTY.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,061,919 Miller May 13, 19131,318,178 Reed Oct. 7, 1919 1,706,005 Thompson Mar. 19, 1929 1,907,931Henderson May 9, 1933 2,106,332 Wilkins Jan. 25, 1938 2,257,900 CrumOct. '7, 1941 2,307,216 Graham Jan. 5, 1943 2,396,332 McBerty Mar. 12,1946 FOREIGN PATENTS Number Country Date 129,453 Austria Aug. 10, 1932

